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Protein adsorption in two-dimensional electrochromatography packed with superporous and microporous cellulose beads
Dongmei WANG, Guodong JIA, Liang XU, Xiaoyan DONG, Yan SUN
Frontiers of Chemical Engineering in China. 2009, 3 (3): 229-234.
https://doi.org/10.1007/s11705-009-0213-6
Anion-exchange superporous cellulose (DEAE-SC) and microporous cellulose (DEAE-MC) adsorbents were packed in an electrochromatographic column, and the effect of external electric field (eEF) on the dynamic adsorption was investigated. The column was designed to provide longitudinal, transverse or 2-dimensional (2D) eEF. It was found that the electro-kinetic effect caused by the introduction of an electric field played an important role in the dynamic adsorption of bovine serum albumin to the adsorbents. The dynamic binding capacity (DBC) in the presence of 2D eEF was higher than in the presence of a one-dimensional eEF. The effect of flow velocity on the DBC of the two adsorbents was also demonstrated. It was found that the effect of electric field on the DEAE-MC column was more remarkable than that on the DEAE-SC column at the same flow rate, whereas the DEAE-SC column showed higher DBC and adsorption efficiency (AE) than the DEAE-MC column. With increasing flow rate, the DEAE-SC column could still offer high DBC and AE in the presence of the 2D eEF. For example, a DBC of 21.4 mg/mL and an AE of 57.7% were obtained even at a flow rate as high as 900 cm/h. The results indicate that the 2D electrochromatography packed with the superporous cellulose adsorbent is promising for high-speed protein chromatography.
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Simultaneous saccharification and fermentation of wheat bran flour into ethanol using coculture of amylotic Aspergillus niger and thermotolerant Kluyveromyces marxianus
K. Manikandan, T. Viruthagiri
Frontiers of Chemical Engineering in China. 2009, 3 (3): 240-249.
https://doi.org/10.1007/s11705-009-0205-6
Studies on simultaneous saccharification and fermentation (SSF) of wheat bran flour, a grain milling residue as the substrate using coculture method were carried out with strains of starch digesting Aspergillus niger and nonstarch digesting and sugar fermenting Kluyveromyces marxianus in batch fermentation. Experiments based on central composite design (CCD) were conducted to maximize the glucose yield and to study the effects of substrate concentration, pH, temperature, and enzyme concentration on percentage conversion of wheat bran flour starch to glucose by treatment with fungal α-amylase and the above parameters were optimized using response surface methodology (RSM). The optimum values of substrate concentration, pH, temperature, and enzyme concentration were found to be 200 g/L, 5.5, 65°C and 7.5 IU, respectively, in the starch saccharification step. The effects of pH, temperature and substrate concentration on ethanol concentration, biomass and reducing sugar concentration were also investigated. The optimum temperature and pH were found to be 30°C and 5.5, respectively. The wheat bran flour solution equivalent to 6% (w/V) initial starch concentration gave the highest ethanol concentration of 23.1 g/L after 48 h of fermentation at optimum conditions of pH and temperature. The growth kinetics was modeled using Monod model and Logistic model and product formation kinetics using Leudeking-Piret model. Simultaneous saccharificiation and fermentation of liquefied wheat bran starch to bioethanol was studied using coculture of amylolytic fungus A. niger and nonamylolytic sugar fermenting K. marxianus.
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Study on the crystal morphology and melting behavior of isothermally crystallized composites of short carbon fiber and poly(trimethylene terephthalate)
Mingtao RUN, Hongzan SONG, Yanping HAO
Frontiers of Chemical Engineering in China. 2009, 3 (3): 255-264.
https://doi.org/10.1007/s11705-009-0008-9
The spherulites of the short carbon fiber(SCF)/poly (trimethylene terephthalate) (PTT) composites formed in limited space at designed temperatures, and their melting behaviors were studied by the polarized optical microscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM), respectively. The results suggest that SCF content, isothermal crystallization temperatures, and the film thicknesses influence the crystal morphology of the composites. The dimension of the spherulites is decreased with increasing SCF content, but whether banded or nonbanded spherulites will form in the composites is not dependent on SCF content. However, the crystal morphology of the composites depends strongly on the temperature. When the isothermal crystallization temperatures increase from 180°C to 230°C, the crystal morphology of SCF/PTT composites continuously changes in the following order: nonbanded → banded → nonbanded spherulites. Discontinuous circle lines form in the film when the film thickness increases from 30 to 60 μm. Basing on the SEM observation, it is found that these circle lines are cracks formed due to the constriction difference of the different parts of the spherulites. These cracks are formed when the film is cooled from the isothermal crystallization temperature to the room temperature at a slow cooling rate; while they will disappear gradually at different temperatures in the heating process. The crack will appear/disappear first around the center of the spherulite when the film was cooled/heated. The nontwisted or slightly twisted lamellas will reorganize to form highly twisted lamellas inducing apparent banded texture of the spherulites.
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Preparation and characterization of alumina hollow fiber membranes
Tao WANG, Yuzhong ZHANG, Guangfen LI, Hong LI
Frontiers of Chemical Engineering in China. 2009, 3 (3): 265-271.
https://doi.org/10.1007/s11705-009-0010-2
With the rapid development of membrane technology in water treatment, there is a growing demand for membrane products with high performance. The inorganic hollow fiber membranes are of great interest due to their high resistance to abrasion, chemical/thermal degradation, and higher surface area/volume ratio therefore they can be utilized in the fields of water treatment. In this study, the alumina (Al2O3) hollow fiber membranes were prepared by a combined phase-inversion and sintering method. The organic binder solution (dope) containing suspended Al2O3 powders was spun to a hollow fiber precursor, which was then sintered at elevated temperatures in order to obtain the Al2O3 hollow fiber membrane. The dope solution consisted of polyethersulfone (PES), N-methyl-2-pyrrolidone (NMP) and polyvinylpyrrolidone (PVP), which were used as polymer binder, solvent and additive, respectively. The prepared Al2O3 hollow fiber membranes were characterized by a scanning electron microscope (SEM) and thermal gravimetric analysis (TG). The effects of the sintering temperature and Al2O3/PES ratios on the morphological structure, pure water flux, pore size and porosity of the membranes were also investigated extensively. The results showed that the pure water flux, maximum pore size and porosity of the prepared membranes decreased with the increase in Al2O3/PES ratios and sintering temperature. When the Al2O3/PES ratio reached 9, the pure water flux and maximum pore size were at 2547 L/m2·h and 1.4 μm, respectively. Under 1600°C of sintering temperature, the pure water flux and maximum pore size reached 2398 L/(m2·h) and 2.3 μm, respectively. The results showed that the alumina hollow fiber membranes we prepared were suitable for the microfiltration process. The morphology investigation also revealed that the prepared Al2O3 hollow fiber membrane retained its’asymmetric structure even after the sintering process.
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Soybean drying characteristics in microwave rotary dryer with forced convection
Ruifang WANG, Zhanyong LI, Yanhua LI, Jingsheng YE
Frontiers of Chemical Engineering in China. 2009, 3 (3): 289-292.
https://doi.org/10.1007/s11705-009-0022-y
A new hybrid drying technique by combining microwave and forced convection drying within a rotary drum, i.e., microwave rotary drying, was developed with the purpose to improve the uniformity of microwave drying. In a laboratory microwave rotary dryer, rewetted soybean was utilized as experimental material to study the effects of drum rotating speed, ventilation flow rate, and specific microwave power on the drying kinetics and cracking ratio of soybean. It was found that, with rotation, the cracking ratio can be lowered but without distinct improvement in the drying rate. Increasing ventilation flow rate and specific microwave power can improve the drying rate, but the cracking ratio also increases as a negative result. The cracking ratio lower than 10% can be attained for ventilation flow rate lower than 2.0 m3·h-1 or specific microwave energy lower than 0.4 kW·kg-1 in the present experiments.
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Design, synthesis, and antiviral properties of 2-aryl-1H-benzimidazole-4-carboxamide derivatives
Xianjin LUO, Zhonglü ZHANG, Yutian YANG, Fei XUE, Naiyun XIU, Yuanbin SHE
Frontiers of Chemical Engineering in China. 2009, 3 (3): 305-309.
https://doi.org/10.1007/s11705-009-0021-z
A series of new benzimidazole derivatives were designed and synthesized. Their chemical structures were testified by 1H NMR, infrared spectroscopy (IR), mass spectrography (MS), and elemental analysis. Their potent antiviral properties indicated the prospect of new drugs. Compound 13, 16, 18, 19, 21, 22, and 23 were identified as novel antivirus with much better selective activity and inhibitory activity than the comparable ribavirin against Coxsackie virus B3 in VERO cells.
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